-HobbyKing.com Sbach 300 1400mm Balsa Plane-

Build Manual

http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=45296&aff=618223

Although this model came with some half decent build instructions on a disk,

they didn’t cover everything and some things were rather vague. So here

goes my version of the build and hopefully it’ll help you along as well.

It is highly suggested you read though this entire manual before

commencing work on your model. I find with myself, when I only read parts

of the manual and try and build in between, I tend to miss steps. So it’s best

to partly familiarize yourself with the whole process first.

Let’s start with what you get…

List of Hardware included -

Landing Gear:

1. Carbon Fiber Landing Gear legs. x 1 2. 2 inch Foam Wheels x 2 3. Wheel Axels and nylon locking nuts x 2 ea. 4. Axel Collets x 2 5. Tail Wheel assembly and mounting screws 6. Fiberglass Wheel Pants (Black) x 2

Elevator:

1. Fiberglass Control Horns and slot protectors x 2 2. Ball-links x 4 3. Pushrods x 2 4. Fiberglass Elevator half joiner

Wing:

1. Fiberglass Control Horns and slot protectors x 2 2. Ball-links x 4 3. Pushrods x 2 4. Nylon wing bolts x 2

Rudder:

1. Fiberglass Control Horn x 1 2. Pull-pull cable x 2 3. Ball-links x 4 4. Brass Eyelet Screws x 4 5. Aluminum crimps x 4 6. Breitling Logo Stickers x 1

Motor:

1. Quality hard plastic Spinner and back plate x 1 2. Aluminum Prop shaft collets for Spinner x 2 3. Small screws for Spinner x 2 4. Motor mounting bolts x 4 5. Motor mounting Screws x 4 6. Nylon spacers for motor mounting x 4

Miscellaneous:

1. CA Hinges x 19 2. Servo Extension Locks x 4 3. Hook & Loop fastener x 2 lengths 4. Sticky backed hook & loop fastener x 1 length

List of Body Parts –

1. Pre-covered Fuselage x 1

2. Pre-painted Fiberglass Cowl x 1

3. Pre-painted Canopy/Battery Hatch x 1

4. Pre-covered Left Wing plus Aileron x 1

5. Pre-covered Right Wing plus Aileron x 1

6. Pre-covered Rudder x 1

7. Pre-covered Horizontal Stabilizer x 1

8. Pre-covered Elevator Halves x 2

9. 580mm x 15mm Extruded Carbon Fiber Wing Spar x 1

Time to Build! Start with the Fuselage and Horizontal Stabilizer (H-Stab).

Starting with the Fuselage, find and cut out all the needed openings, such

as the wing spar, wing bolt and wing alignment guide holes and also the

H-Stab cut-out. The best way to do this by shining a bright flashlight from

behind to locate them all:

(I bought the Scratch & Dent version of this plane from HobbyKing, I believe it was used in a photo

shoot, so the cut-outs were already done for me)

Once you’ve cut the covering film away from where you need, insert the

H-Stab into place and temporarily install the main wings as well:

Now align the H-Stab by measuring front and back on both sides and

diagonally across to the wings making sure all measurements on both sides

are the same to ensure it is straight:

Once it’s aligned, mark the H-Stab by drawing lines on both sides of the

fuselage, on both the top and bottom of the stabilizer:

Once marked out, remove the H-Stab and cut away the covering film

between your marks. I find it’s best to use a hot soldering iron to cut the

covering film as this allows you to do so without cutting the balsa sheet on

the H-Stab. Once this section of film is removed, slide the H-Stab back into

place and glue it there. I use thin CA glue but I know others prefer to epoxy

the H-Stab into place. I’ve never had a problem using thin CA glue though,

so it’s entirely your choice.

Let’s tackle the landing gear (LG) now. Cut away the covering film from the

LG mounting area and screw the LG into place:

HobbyKing went the extra mile with this model and put some extra thought

into engineering the landing gear mounting area.

With previous HobbyKing models this has been an area of weakness, but

they’ve added some extra reinforcement in this area.

Here’s a picture of what they’ve done on the inside of the fuselage for the

LG area:

For a little added security of mind I added a couple 45° bolsters on the

opposite side of the firewall:

Mount the wheels on the Axels using the axel collets, and then loosely

mount the axel and wheel onto the LG:

Take note of the set hole on the axel, this is so you can hold it still by

inserting a rod or hex wrench into the hole while you tighten the axel nut.

Now slide in the Wheel Pant between the axel flange and the LG and snug

everything up:

Don’t tighten the axel nuts fully until you have the wheel pants properly

aligned. They should be mounted so their center line is roughly parallel to

the fuselage bottom. Once done, complete tightening the axel nuts:

Let’s now get started with the Motor and Cowl installment. Here’s where I

had to get a bit creative because the motor mount seems too large for the

cowl and forced it into a “nose up” attitude:

My solution was to sand down the motor box until the cowl fit correctly:

Due to the measurements of my motor I had to move it forward about a ¼

inch. So I epoxied in another plywood mount and then mounted my motor:

ESC is mounted nicely in the airflow on the side of the motor box. Now is a good time

to temporarily connect your radio and ensure the motor is turning the correct direction.

I suspect if you purchase one of HobbyKing’s SK3 Series line of motors it

will fit the pre-installed blind nuts for the motor mount. Once the motor is

mounted, slide the cowl into place and center it on the motor for alignment:

Once aligned, tape it into place:

Note: The 2 side pieces of tape were previously placed and marked where I wished to drill for

the mounting screws. I then peeled them pack, not removing them, so once the cowl

was aligned and in place I rolled the tape forward back into position so the marks I

made went back into place over the cowl mounting blocks.

I test fit the spinner back plate onto the motor shaft to ensure the gap between the cowl and back plate wasn’t too large. This is just a matter of ascetics, I dislike large gaps here.

Once you’re happy with the fit, drill and mount the cowl with the included screws. (Just a note, I had to dremel out a couple slots on the bottom of the cowl to slide over the landing gear legs):

Install the rudder and ailerons using either the CA Hinges included or hinges of your choice:

Install the tail wheel assembly. This is a simple installation. Drill a 1/16th hole

on the bottom of the rudder and thread in the brass eyelet screw. Put a drop of thin CA glue where it enters the rudder to secure it. Then slide the tail wheel guide wire through the eyelet screw and secure the tail wheel assembly to the fuselage using the two 1/16

th inch included screws:

Now let’s install the Elevators. Sand the Elevator joiner to rough it up for gluing:

Glue it with epoxy into one half of the elevator:

Now place this side of the elevator onto the CA hinges on the stabilizer, sliding the joiner through the elevator opening in the fuselage. I use head pins through the center of the CA hinges to keep them centered between the Stab and the Elevator (do not glue in place yet):

Put epoxy glue into the joiner slot in other elevator half and slide it onto the Stab and the joiner with the CA hinges in place. (Before the epoxy sets up, tape both halves of the elevator to the Stab to make sure they are straight as the epoxy dries):

Once the epoxy has cured, pull off the tape so you can open up the hinge line and glue the hinges with thin CA. (If you were using different hinges, you may have to epoxy them at the same time as the joiner):

Now find and cut out the mounts for your servos and the control horn slots for the ailerons and elevator. (For the slots, cut a little extra film away from them to glue the fiberglass slot protector to):

Rough up one side of the fiberglass slot protector with sand paper and glue the rough side to the exposed balsa where you trimmed the film:

Now glue in the control horn:

Mount your elevator servo. Thread two ball-links onto one of the longer elevator pushrods. Only thread them on half way to allow for adjustment either direction. Temporarily install your radio gear and power up your elevator servo to help while installing the servo arm and pushrod to the correct position and length. (It doesn’t hurt to re-tape the Elevator to the Stab to hold the elevator in position while fitting the pushrod):

Note: Enough hardware is included that you can choose to install a second

Elevator servo on the opposite side. However, with the two elevator halves

being joined, I don’t feel this is necessary unless you feel you need the

extra control strength.

Install the Aileron servos and hardware in the same manner:

Now we’ll install the Rudder control horn and Pull-Pull system. Cut the slot for the control horn in the rudder; do not cut the film away from the slot like we did for the elevator and aileron control horns. Also cut out the slots where the cable will exit the fuselage on both sides:

Slide the Rudder control horn through the slot and glue into place:

Install your rudder servo into the fuselage area. You should use a servo horn that is approximately the same length in total as the rudder control horn:

Thread the brass eyelet screws into the ball links. (Once again, only thread them in about half way as we’ll need to screw them in to tighten the cable later):

Install the ready ball links onto both the rudder control horn and the servo horn.

Now on the rudder control horn, attach the pull-pull cables to the eyelets. The best way is to thread the cable through the eyelet hole, slide the crimp tube into place, then thread the short end of the cable through the crimp tube and loop it back around through the crimp tube again:

Then pull everything tight, using your finger to help the loop pull tight. Finally, use a narrow pliers or crimp tool and crimp the tube to the cable. Trim the excess cable off with a wire cutter.

Once you have the cable attached to both sides of the rudder, thread the cables into the fuselage one at a time and attach them to the eyelets on the servo horn the same way. Make sure to slide on the crimp tubes first.

In order for this system to work in this fuselage you will need to cross the cables over to the opposite side of the servo horn. For example, when looking at the model from the rear, the cable attached to the left rudder control horn will cross over in the fuselage to the right side of the servo horn. The cable attached to the right side of the rudder control horn will cross over to the left side of the servo horn. Before securing the cables onto the ball links on the servo horn, pull each cable relatively tight. You will probably want to power up your radio system to hold the rudder servo centered. Once the cables are fairly tight, go ahead and crimp them in place like you did on the rudder control horns and cut off any excess cable.

With your radio system still on, start tightening the cables by screwing in the eyelets into the ball links further. The cables should be just tight enough so they do not droop in the fuselage. You’ll have to tighten each side on each end in such a way so that when you’re done the rudder is centered with the rudder servo being held neutrally centered by your radio system. (Note: After a few flights you will need to tighten the cables a little more as they’ll stretch a bit with use).

This is also a good time to final adjust your other servo linkages to ensure all control surfaces are centered while the radio system is holding the servos centered as well.

A note on servo wire extensions: Both the elevator servo and the aileron servos will need servo wire lead extensions. Included in the hardware are servo plug locks for the extensions. If you haven’t used them before, they are clipped onto the servo plugs between the extension and the servo to keep them from coming apart in flight:

Now is also a good time to finalize your radio installation to your liking:

Reinstall the wings and plug your aileron servos into your receiver. Plug your elevator and rudder servos into the receiver as well. I installed an external BEC in line with the ESC. I prefer using an external BEC because while flying slow high alpha maneuvers the airflow is reduce over the ESC and there is always a possibility of a burnout. If your ESC fries it’s nice knowing you’ll still have control over your flight controls to hopefully land the aircraft in one piece.

Install your propeller and spinner onto your motor:

You can now test your radio system to ensure everything is working correctly and that all of your control surfaces are moving the correct direction for your control stick movements.

You should now be ready for your maiden flight!

Model Specs:

Wingspan: 1400mm Length: 1357mm Wing Area: 38.14dm2 Flying Weight: 2100g

Center of Gravity:

110mm from wing leading edge

Suggested Electronics:

Motor: 35xx 1000w

Battery: 4s 2600-3000mAh

ESC: 50-80A (Depending on motor)

Radio: 4-6 Channel

Servos: (4 to 5) 26-29g Digital Metal Gear

Prop: 13 to 16 inch

This Instruction Manual was put together by me, Perry Wolf, in the hopes that it will better guide you towards your first successful flight.

I can be found on RCGroups.com under the username “teknokraze” should you have any further questions.

Regards,

Perry Wolf.